of dayton



July 3l, 1923- 1,463,513

c. L.. LEI;

ELECTRIC FURNACE:

2 Sheets-Sheet l Filed April 13. 1921 `\\\\\\\\\v uw lll 'Ill'llllllllllllllllllllll July 2.1` 1923 CI.I.. LEEE ELECTRIC FURNACE Filed April 13. 1921 2 Sheets-Sheet 2 Patented July 3l, 1923.

UNITED STATES PATENT OFFICE.

CHARLES L. LEE, OF DAYTON, OHIO, ASSIGNOR TO GENERAL MOTORS RESEARCH CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE.

ELECTRIC FUBNACE.

Application filed April 13, 1921. Serial No. 460,924.

To all 'whom 'it may concern? Be it known that I, CHARLES L. Las, a citizen of the United States of America, resdin at Dayton, county of Montgom er an State of Ohio, have invented certain new and useful Improvements in E lec tric Furnaces, of which the following 1s a full, clear, and exact description.

The present invention relates to electric furnaces and in its preferred form of embodiment, which has been chosen for .the purposes of description and explanation, to electric furnaces for carrying out a process of attaching cooling ribs or fins to cylinders of internal combustion en ines:

The process referred to, but orniin no part of the present invention, is o ne in w ich after suitable'machinin operations, an assembly of an iron cylin er and cooling ribs or fins, preferably of sheet copper, is made `by wrapping a set of the latter around the cylinder with an interposed sheet of braaing brass and with suitable fluxing. This assembly is then suitably heated to cause the fins to be brazed to the cylinder. This operation produces union between the metal of the cylindersand that of the cooling elements which is permanent and offers no substantial impediment to the passage of heat from one metal to the other.

It is among the objects of the present invention to provide a furnace for carrying out the above processi Another object is to provide a furnace which is efficient, economical, and easily and exactly controlled,

Further objects and advantages of the resent invention will be apparent from the ollowing description, reference beinghad to the accompanying drawings, wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Fig. 1 is a sectional view, with parts in elevation, of the furnace assembly with a cylinder in placeV Fig. 2 is a vidw in elevation of the collector rings for the resistors with the resisters attached.

Fig. 3 is an end view of the furnace along the line of Fig. 1 with parts in section and parte ,in elevation.

Fig. 4l a perspective view of a resistor and its .ho der showing clearly the adaptation of the holder for the resistor.

As is illustrated in the drawings the furnace assembly 10 is suitably mounted upon a base 11 having thereon supportin members 12 for rollers 13 and 14 whic carry the furnace. Also mounted upon this base is the electric heating unit assembly designated as a whole by the numeral 15.

ix The furnace is adapted to be rotated about its longitudinal axis and is caused to `revolve by means of the rollers 13 and 14 carried by a suitable drive shaft 16. l'n my prior application for patent, Serial No.

396,276, filed July 14, i920, on Furnaces,

now Patent No. 1,445,220, dated February 13, 1923, there is described suitable means for driving a corresponding shaft in a similar furnace. In that application the means comprises a gear mounted on the end of the shaft which corresponds to shaft 16, which gear is driven by a worm carried by a shaft directly connected to a motor. For clearness and simplicity of illustration, this driving apparatus is omitted, and itv should be understood that any suitable driving means may he used.

Ylcferring more particularly to Fig. 1, the furnace consists of a casing 20, preferably cylindrical, which has bearin rings 21 around its periphery for the ro ers 13 and 14. The casing is suitably heat insulated as at 22, preferably with transite or other composition containing asbestos, suitable means such as an inner cylindrical member 23 being provided for retaining the insulating material in place.

A closure late 25 havin a central opening is provi cd for one en of the furnace and is preferably integral with the casing. At the other end, however, the closure plate 26 is removable and preferably hinged at 27, as illustrated, and adapted to be secured in place in an suitable manner as indicated at 28. oth closure plates are rovided at their inner faces with suitable eat insulating material 29 such as transite as mentioned above, which material at the plate 26 is preferably removable along with the plate itself.

The heating unit 15 comprises a supporting bracket 30 having attached rigidly thereto, an extended portion 31 for holding a tube 32 which extends through the opening in plate 25 centrally within the furnace and is adapted to support the heating elements hereinafter mentioned. Also supported by the bracket 30 are electric insulating plates 35 and 36 adapted to support the collector rings 37 and 38. Attached to these collector ringsare a plurality of U-shaped electric resistors or heating elements 40, which are held against the rings by. means of suitable clamping rings 41, 41', and bolts 42 42.

Referring to Fig. 4, it will be noted that the'terminalV ends of each resistor 'are bent substantially aty'right angles and at different distances from the closed end 44, as illustrated at 45 and 46, to permit the attachment of each resistor at its terminal ends to both collector rings. As shown in Fi 2, each terminal end 45 may be at tac ed to the outer collector ring 37, which corresponds electrically to the negative terminal of, the heating unit, and clamped 1n lace by means of the clamping ring 4l and tween the bolts 42. Similarly, cach end 46 may be attached to the inner collector ring 38, corresponding to the positive termina] and clamped in place b y the clamping ring 41 and between the bolts 42. This manner of connecting the resistors to the collector rings results in the resistors beingconnected in electric parallel and as a whole offering little resistance to the How of electric current. The collector rings have portions 47 adapted to permit connection to suitable sources of electric current by means of holes 48 for the installation of suitable terminals.

In Fig. 4, is shown, along with the type of resistor preferred, a holder 50 for sup porting these resistors, only one resistor and the means for fitting and holding it 1n the holder being shown for convenience of illustration. Various metals may be found suitable for these resistors, but it is preferred to use nichrome since it has the quality of not oxidizing readily when heated to incandescence for a considerable length of time.

The holder 50 has a pair of grooves 51 for each resistor which grooves are arranged, as illustrated at 53, to form a hook 54. The closed or U-shaped end 44 of the resistor 40 is bent to fit into the grooved portion at 53 and is adapted to coact with the hook 54 to retain the resistor in place in the holder. This holder is made of some good heat and electrical insulating material preferably alundum cement and has a cylindrical hole 56 centrallyV located therein to permit its fitting over the tube 32.

The cylinder assembly 60 upon which the process is to be carried out is shown in ig. 3. The cylinder is assembled, with the fin material as described in the above inentioned application, Serial No. 392,646 and as indicated in Fig. 3 by providing suitable flux therefor, placing the fin material around the cylinder with a sheet of brazing` cylinder assembly and is substantially coaxial with the sleeve 62. In order to protect the heat insulating material 29 on closure 25 from abrasion by the end of the. cylinder assembly, a plate 64 may be provided between the material and the latter, permitting the abutment 0f the cylinder against the plate as it is installed upon the supporting sleeve 62. The plate 26 may be provided with a peep-hole 65 for observing the condition of the cylinder assembly during lthe different stages of the heating operation.

With the cylinder assembly properly in place, the furnace is rotated and electric current is supplied to the heating elements, permitting the carrying out of the process hereinbefore referred to. 1t is evident that, when current is supplied to the resistors causing them to become less capable of retaining their form or place due to the in. luence of the heat generated in accordance with the well known Joules law where PIIQR, the resistors are retained in place by this holder and are prevented from com` ing in contact with the cylinder with possible injurious eifects such as might result from short circuits.

Although the furnace may be operated with various voltages and currents depending upon the' design thereof, it has been found that a relatively low voltage, for example around 8 to l0 volts, and heavy current operate very satisfactorily and adapt themselves very readily to commercial use.

It is obvious that, with various controls for the heating unit, very accurate reproduction of complete units may be obtained, assurin products that are satisfactory and unions etween the metals of the cylinders and cooling elements which are permanent.

Further, While the structure herein shown and described constitutes a preferred form of embodiment of the present invention, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What I claim is as follows:

1. An electric furnace for heating cylinders comprising means for locating the cylinder within the furnace; a heating element; means for locating the heating element within the cylinder; and means for connecting the said element within an electric circuit.

2. An electric furnace for heating cylinders com rising means for locating the cylinder wit in the furnace; a plurality of heating elements; means for locating the elements within ythe cylinder; and means for connecting the elements to a source of electric current.

3. An electric furnace for heating cylinders comprising means for locating the cylinder within the' furnace; a plurality of heating elements; means ada ted to insulate and support the elements wlthin the cylinder; and means for connecting the heating elements to a source of electric current.

4. A rotatable electric furnace adapted to supply heat to a cylinder of an internal combustion engine during the process of attaching coolingy elements thereto and having a heat insulatey casing for the cylinder assembl comprising means for locating the cylin er assembly within the furnace; a reslstance element; a holder-therefor; means for locating the holder within the cylinder; and means for connecting the resistance element within an electric circuit.

5. A rotatable electric furnace adapted to sup A1y heat to a c linder of an internalcom ustion engine uring the process of attachin coolin elements thereto and having a eat insu ated casing for the cylinder assembly comprising means for locating the cylinder assembly within the furnace; a plurality of electric resistors; a holder for the resistors; means for locating the holder within the cylinder; and means for connecting the resistors to a source of electric current.

6. A rotatable electric furnace adapted to supply heat to a cylinder of an aircooled internal-combustion engine durin the process of attaching cooling elements t ereto and having a heat insulated casing for the cylinder assembly comprising means for locating the cylinder assembl within the furnace; a plurality of U-s aped electric resisters; means for locating the resistors at their closed ends within the cylinder; a holder for the portion of the resistors wit in the, cylinder adapted to insulate and retain them in position; and means for connecting the resistors at their open ends to a source of electric current. Y

7. A rotatable electric furnace adapted to supply heat to a cylinder of an air-cooled internal-combustion en ine for brazing cooling fins to the walls t ereof `and having a heat insulated casing for the cylinder assembl comprising means for locating the cylindler assembly within the furnace; a plurality of U-shaped electric resistors; an insulatin holder having longitudinal grooves for resistor velements and with the closed ends of the resistors to retain them in place in the grooves; a sup ort for the holder adapted to locate the ho der centrally within the cylinder; and collector rings for those portions of the resistors external to the furnace casinor adapted to Connect the resistors in parallel to a source of electric current/ In testimoliy whereof I hereto aflx my signature. l

CHARLES L. LEE. Witnesses:

R. K. Lan,

adapted to coact 

